Rheostat



(No'ModeL) 3 Sheets-Sheet. 2. A. o. DINKEY RHBOSTAT.

N0. 51-8, 365. U Patented Apr. 17, 1894,

INVENTOR WGMHDM- (No Model.) 3 Sheets-Sheet 3.

A. C. DIN-KEY. RHEOSTAT.

No. 518,365. Patented Apr. 17,1894.

WITNESSES INVENTOR UNETED Sterne PATENT Genres.

RH EOSTAT.

SPECIFICATION forming part of Letters Patent N 0. 518,365, dated April17, 1894.

Application filed December 1, 1393- To all whom it may concern:

Be it known that l, ALVA O. DINKEY, residing in the county of Alleghenyand State of Pennsylvania, have invented a new and useful Improvement inRheostats, of which the following is a full, clear, and exactdescription, reference being had to the accompanying drawings, formingpart of this specification, in which- Figure l is a front elevation ofmy improved rheostat. Fig. 2 is a cross section on the line II-'-II ofFig. 1. Fig. 3 is a rear elevation showing the reversing switch andconnections. Fig. 4 is a detail view of the brushes. Fig. 5 is a partialrear elevation showing the parts in operative position. Fig. 6 is adetail view of the segmental racks and their pinions. Fig. 7 is anenlarged plan View partly in section, of the'arc extinguisher; and Figs.8 to 11 inclusive are detail views of the parts of the extinguisher.

My invention relates to the class of rheostats, and is designed tosimplify and lighten their construction, to render them easier ofoperation, to do away with the necessity of two sets of contacts foreach resistance box, and to prevent sparking.

In the drawings, 2 and 3 represent the front and rear faces respectivelyof the rheostat box or frame. Passing through these faces is a centralshaft 4 to whose front end is attached the traveling contact arm 5, itbeing fitted in a suitable trough-shaped depression in the plate 6secured to the shaft, a suitable layer of insulating material beingemployed in the trough or groove, as well as beneath the nuts 7 whichsecure the arm. To this arm are secured the two sets of contact brushes8 and 9, one set 8 passing over the contact pieces connected totheresistance boxes, while the other passes over the arc-shaped continuouscontact-piece 11. The vertical operating lever 12 is keyed to the shaft13, which carrise a segmental rack 14 intermeshing with a pinion 15,which is loose upon the shaft 4, but is integral with a collar carryingat its outer end beyond the rear face of the box the disk 16. This diskcarries a single tooth 17, which engages the similarly toothed leverarm18 of the reversing switch 19. This switch is provided with two arms 20and 21,

which carry the positive and negative wires Serial No. 492,413. (Nomodel.)

respectively, and pass beneath the raised contact pieces 22, 23 and 24.The contact pieces 22 and 24 are connected together, and it is p evidentthat the current may be reversed by reversing the direction of rotationof the switch, one arm contacting with the piece 23 whenever the othermoves beneath the piece 22 or 24. The disk carries a crank-pin 25, whichis connected with a lever 26 by the rod or link 27. This crank-pin is solocated relatively to the end of the lever-arm, that the three centers,2'. e., the center of the disk and the two pivots of thelink, shall bein a straight line (the reversing switch standing open) whenever theactuating lever is in normal position.

When the lever is moved in either direction, it actuates the disk,moving the reversing switch and at the same time moves the lever 26 inthe direction shown in Fig. 5, the link pushing upon the lever whetherits crank-pin moves in one direction or the other. Upon the shaft of thelever 26 is carried a second segmental rack 27, which engages a pinion28 (Fig.2) keyed to the shaft 4. Thus the traveling contact arm isalways moved in the same direction by any motion of the lever from itsnormal position, while the direction of movement of the switch dependsdirectly upon that of the lever.

To prevent the sparking and formation of an are as the arm leaves thefirst contact piece 11, I provide on the front face the stationarycylinder 29, having the spring-pressed piston 30 provided with aprotruding piston-rod 31, and having its opposite outer head providedwith a series of inlet ports 32, having inwardly-opening valves formedby an annular thin diaphragm 34. From the rear end of the cylinder,leads a bent or curved pipe 35, which terminates in a vertical long thinmouth or outlet port 36 situate at the end of the contact piece 11.Whenever the traveling contact arm returns to its normal position, itpresses upon the piston-rod 31, and forces a quick puff of clean pureair through the aperture 36, which blows out any spark or are which mayhave formed, and drives away the metallic gases or vapors which enableit to form.

The advantages of the device will be apparent to those skilled in theart, since only one set of contact plates is needed for the coils, thearm always moving in the same direction, while the current is reversedby reversing the movement of the lover. The reversing switch moves onlya small distance, as the tooth then leaves the lever 18, which is thenguided upon the edge of the disk, and locked by said edge and contacts22, 23, and 2e, as shown in Fig. 5, so that the tooth will again engageupon its return. This does away with a large amount of labor in movingthe switch and greatly simplifies the device. The blower is entirelyautomatic and performs its work effectively, and the entire device iscompact and not liable to get out of order.

' Variations in the form, arrangement and construction of the parts maybe made by the skilled mechanic Within the scope of the claims, sinceWVhat I claim, and desire to secure by Letters Patent, is-

1. In a rheostat, a reversing switch having a projecting arm, a plate ordisk having a tooth to engage the arm, and means for actuating the disk;substantially as described.

2. In a rheostat, a shaft having a lever, a connection between saidshaft and a collar upon a second shaft, a crank-pin carried by thecollar, a link pivoted to the crank-pin and to a lever arm, and anactuating connection between the lever arm and the traveling contact armof the rheostat; substantially as described.

3. In a rheostat, a shaft having a lever, a connection between saidshaft and a collar upon a second shaft, a crank pin carried by thecollar, a link pivoted to the crank-pin and to a lever-arm, and aconnection between the lever-arm and the second shaft; substantially asdescribed.

4. A rheostat having a cylinder provided with a projecting piston rod,and a pipe leading from the cylinder, substantially as described.

5. A 'rheostat having a stationary cylinder at one end of the contactpieces, a projecting piston rod, valve-controlled air inlet ports, apipe leading from the cylinder, and a contact arm arranged to actuatethe piston-rod; substantially as described.

In testimony whereof I have hereunto set my hand.

ALVA G. DINKEY,

Witnesses:

F. E. GAITHER, 1-1. M. Conwm.

